1. Field of the Invention
This invention relates to picture output devices, and more particularly to picture output devices capable of coping with a plurality of kinds of video signals.
2. Description of the Related Art
The present broadcast television systems are standardized, for example, according to the NTSC, based on an individual picture having 525 horizontal scanning lines with the use of the interlaced scanning technique. By the way, as video printers or the like have been developed, and further as an improvement of the quality for still pictures is demanded, there are increasing opportunities for dealing with a television signal as modified from the NTSC signal by using different scanning methods. For example, a signal of non-interlaced 525 horizontal scanning lines, and another signal of interlaced 1051 horizontal scanning lines have come to be used in television systems.
In the present situation where, as has been mentioned above, the available television signals are of different forms taken independently of each other, when one desires to view one of the other kinds of video signals than that adapted to the receiver he already has, another receiver must be bought. That is, since the shape of the fluorescent screen is usually conformed to the aspect ratio of the video signal, for a video signal whose aspect ratio does not match the used receiver, it will result that either part of the picture cannot be displayed, or part of the area of the screen is not used to display the picture. The former implies that the integral part of the picture information is abandoned. This is by no means desirable. The appearance of a blank along with the picture on the fluorescent screen in the latter case will give an unpleasant impression to the viewer.
To be adaptable to two different kinds of video signals by having the two receivers at hand, the user is obliged to pay a high cost, and further needs to prepare a space they occupy on the shelf or the like. Hence, the user now is encountering a very inconvenient situation.